1. Field of the Invention
The present invention relates generally to an image forming apparatus for color printing, and, more particularly, to an image forming apparatus that detects whether a process cartridge, etc., that is removably attached to the image forming apparatus for use is a certified part or an uncertified part and that enables image forming by changing an image process without disabling all image forming functions of the image forming apparatus, as well as to a method for controlling the image forming apparatus and a storage medium for storing a program for controlling the image forming apparatus.
2. Description of the Related Art
Common image forming apparatuses employing an electrophotography scheme such as printers, copiers, fax machines, or the like, form images by first forming a latent image through selective exposure of a photosensitive drum that is uniformly charged, developing this latent image into a visible image with toner that is the developing agent, and then transferring the toner image onto a printing medium.
Because the toner is consumed in this manner, the toner must be replenished for the image forming apparatus every time the toner has run out. However, the refilling or replenishing the toner is a burdensome, and often dirty, task. Complicating the matter, for many machines, only dedicated service staff are able or allowed to perform such maintenance of the image forming apparatus.
On the other hand, some known image forming apparatuses facilitate maintenance by employing a process cartridge which integrates a developing apparatus, and other units into a single structure which is freely detachable from the main body of the image forming apparatus. Such a configuration enables a user to simply replace the process cartridge when the toner has been used up or when a part such as a developing roller, or the like has reached the end of its service life.
One such apparatus is configured as a color image forming apparatus, a rotation-switching-type (rotary-type) color developing apparatus, or a tandem-type color developing apparatus which is provided with four developing cartridges, each accommodating a respective developing unit for each of four colors of black, cyan, magenta, and yellow. In this apparatus, each of the cartridges is freely detachable from the main body of the apparatus.
Such cartridge-type image forming apparatuses are designed with the intent that users will replace the cartridges themselves. Therefore, means are necessary for notifying the user of the fact that the toner level is low or that a part such as a developing roller, or the like has reached the end of its service life.
A method has also been presented and employed that enables data on the amount of used toner in a cartridge to be stored by providing a nonvolatile memory such as an EEPROM or the like to the cartridge for detecting the life of a part or the toner consumption, and by accumulating in the memory the data on the amount of toner used. For example, when the photosensitive drum is exposed using a laser, section for adding and storing information of exposure time and information relating to the amount of remaining toner may be provided.
Usually, a manufacturer of an image forming apparatus assumes that replacement parts for which the manufacturer can confirm the safety, such as original or certified replacement parts, will be attached, and designs and manufactures the main body of the apparatus such that predetermined image quality and safety performance can be obtained under those conditions.
When replacement parts of which use is not certified (uncertified parts) such as imitations, counterfeits, pirated copies, etc., are attached to the main body of the apparatus designed and manufactured as above, their operation is beyond the scope of the manufacturer's assumptions. Therefore, a user may suffer from various disadvantages. For example, problems with image quality, malfunctions, faults in the main body of the apparatus, physical damage of the printing paper (tearing, wrinkling, etc.,), or serious accidents (noise, smells, sparking, smoking, explosions, etc.,) may occur.
In order to avoid the above disadvantages, a technique is employed, for automatically determining whether or not an attached replacement part is an original or authorized part or the like, and, when the attached replacement part is not an authorized part, prohibiting the image forming operation or displaying an alarm (See, for example, Japanese Patent Application Laid-Open Publication No. 2001-337565).
As described above, use of a replacement part (herein after referred to as “CRU (Customer Replaceable Unit)”) which use is not certified by the manufacturer such as an imitation (uncertified part) is not preferable from the viewpoints of safety and other considerations, However, among consumers, many consumers desire to use uncertified parts, not only for image forming apparatuses but also widely for apparatuses to which CRUs can be attached. Despite this, in the conventional technique, the image forming function is completely disabled, even when even only one uncertified CRU is detected.
Then, when, in a color image forming apparatus, it should still be possible to form or print an image using just the certified parts, all image forming is prohibited, which clearly inconveniences consumers.